Spindle Cooling Fan Direction

On a Fadal mill, does the spindle cooling fan pull the warm air out or suck the outside air in?

specgrade said:

On a Fadal mill, does the spindle cooling fan pull the warm air out or suck the outside air in?

Click to expand...

I believe it should pull the warm air out and not blow dirty outside air in. Am I wrong about this? Thank you!

I don't have any fadals- but on my CNC's, all the fans on the enclosures and motors exhaust warm air.

The only fans that blow in (IIRC) are the little ones mounted to heat sinks. And my air compressor, which has a pressurized enclosure.

guest said:

I don't have any fadals- but on my CNC's, all the fans on the enclosures and motors exhaust warm air.

The only fans that blow in (IIRC) are the little ones mounted to heat sinks. And my air compressor, which has a pressurized enclosure.

Click to expand...

Thank you so much. Our service guy has the fan blowing in towards the spindle and,to me, that's not right.

I prefer positive pressure or blowing in.
This way you can filter the air source before it gets to the spindle or other things along with knowing where the air inlet is.
IBM actuality patented this for shop floor computers but it never held up in court.
On a exhaust or sucking type type system you have no control over the incoming air quality so you may well be bringing in coolant filled air.
One of these after decades of use leaves you much cleaner guts.
This is not to mention the efficiency problems of pushing air verses sucking it for a typical fan design.
I have no idea what the factory rig for your machine was.
Bob

specgrade said:

Thank you so much. Our service guy has the fan blowing in towards the spindle and,to me, that's not right.

Click to expand...

I've done the spindle fans on 2 of my mills. Fanucs. They were obvious- you couldn't install them upside down if you wanted to.

The enclosures all have filters on the air inlets, I don't know how the spindles are.

The fan on top of the Fadal spindle motor blows air into the motor.
On early machines they used open frame motors and sold a filter kit to keep the coolant mist out of the windings.

Later machines used a totally enclosed motor with a 1/4 gap around the end bell, the air flow would blow along the outside of the motor.

A filter is a good idea either way, you can still buy them or make your own with NAPA #2011 and top plate with 2 standoffs.
Mine get changed once a year and they need it.

Factory our Fadals exhaust the air up however for best cooling blowing down on the motor would be more efficient in cooling. I say this because of the flow direction stickers on the fan housing show it spins to the right. Unless they were affixed wrong? Anyways if you think about it this way when you lick your finger and hold it in the air to see which direction the winds blowing does your finger feel cold or warm? How about trying to suck air past it, good luck noticing any cooling effect. Same goes for a vehicle radiator. Does the fan blow the air out the front or does it blow the air in? There is a reason for this. Perhaps the motors don’t require the cooling that blowing across the motor would perform however if you were tossing an air filter on the top why not draw the air into the filter and down over the motor? I believe the factory had them blow upward to try and keep the coolant and junk from dripping down but our 4020 we had to clean the motor out because there was over 1/2” of goo and chips built up so we added a filter and kept it blowing downward to keep the encoders and motor cooler during operation. Noticed an approx 20 degree drop in exterior temps so it’s clear which works better but is it necessary? We tend to always feel if the factory did it one way that we shouldn’t change it. Ultimately it’s up to the individual to decide and probably a preference in this case.